My plant obsession

Propagating Cotinus by softwood cuttings

I have a Cotinus ‘Grace’ shrub in my garden. It’s not very old, 3 years maybe, plus whatever growing time it had before I bought it. It gets to a decent height, about 2m, and is an impressive feature shrub. Left unmolested they can grow quite large, up to 6m in height. I grow it for foliage colour rather than flowers.

Fantastic foliage. (Image crocus.co.uk)

To encourage foliage of a good size and colour, it is recommended to prune hard in early spring. So, early this year I cut mine back to the framework. In the last couple of weeks, new shoots have begun to emerge. This is always a relief after a brutal haircut like this, I always worry that I’ve finished it off. It’s such a good shrub, I would like another to bookend the same border, so I am trying hard to propagate the damn thing. Last winter I tried hardwood cuttings which have shown zero signs of doing anything, I suspect they are merely dead sticks. I’m going to give them a bit longer but then I’ll cut my losses. It turns out that cotinus are not recommended for hardwood cuttings, and I can now concur (the RHS were waiting for me to confirm this, I’m sure…). Instead, softwood cuttings can be taken. These are the immature stems of growth put on in the current year. May and June are typical times for this type of cutting, at least in southern England. Mine is pruned back to the bone, so all the growth is new.

New stems post-pruning

As described in my similar post on clematis, softwood cuttings require considerably more TLC than hardwood cuttings, they will wilt very quickly after cutting. Unless you are going direct from shrub to setting up, it’s best to put the cuttings in a clear, damp plastic bag, this limits excessive moisture loss. Even then, I wouldn’t linger for too long. It’s also best to make sure everything is prepared before hand, save mucking about. In my case this is mainly about cleanliness. I have learnt through bitter experience that being slapdash about this results in a poor success rate. There’s too much opportunity to introduce contamination that can result in failure during rooting, when the pot is sitting in a hot and humid atmosphere for weeks. I am now much more scrupulous – time will tell if that makes a blind bit of difference to outcomes.

My pre-cuttings routine is as follows:

1) Prepare cuttings compost. I’m using a gritty mix, 2 parts horticultural grit to 1 part vermiculite.
2) Clean everything. I use a kitchen bleach spray. Pot, blade, cutting surface, dibber, clean everything, and again between varieties if you are doing more than one batch. Wash hands too.
3) Fungicide spray. Mix up ready to use. I have a 1 litre spray bottle of this ready to roll.
4) Put the cuttings compost in the clean pot, wet it thoroughly, then give it a good spray with the fungicide

With all that done, for the cotinus, I simply (carefully) pulled off a handful of the stems at the base, then off to propagation HQ to my ready prepped kit.

I had 8 stems to trim and set up.

Softwood cuttings, ready to trim.

They don’t need a great deal of trimming, I’m aiming for a clean stem and just a few leaves at the top. I first trimmed the bottom of the stem, leaving a cutting about 7cm long in total.

First trim.

I then trimmed off any leaves from the remaining part of the stem. All such trimming is done with a sharp blade to avoid any tearing which can leave the stem vulnerable to disease whilst rooting.

All that leaves a cutting that looks like this.

Maintaining good anti-contiminant discipline, I sprayed the stems with fungicide before dipping into rooting hormone powder. I made a hole with the dibber then used it again to ease the prepared cuttings into the pot. If I had taken more cotinus cuttings I would have used more of the available space in the pot, but in the event I was able to crowd them in around the edge of the pot, followed by a good spritz with the fungicide spray.

To maximise the chance of rooting successfully, and to avoid fatal moisture loss, it’s best to put the pot in a heated propagator for bottom heat and also a humid environment. This humidity might be achieved through a clear propagator lid, or failing that, put the pot in a large, clean, clear plastic bag and seal.

One other thing to watch out for which might finish a rooting cutting. At this time of year, direct sunlight can be quite strong, too strong for a tender, sensitive, immature cutting. There’s a balance to be struck between providing enough light for fuel via photosynthesis, and the potential for damage by scorching. A suitable compromise is to add some shade cloth, or a sheet of newspaper, onto the propagator lid. In my case I have some greenhouse shade cloth which I have draped over the clear polythene lid of my heated bench.

Shading

Actually, there are two other things. Whilst such cuttings prefer a humid environment, it is good to ventilate from time to time, just for 10 minutes, say, to allow a change of atmosphere.

Let me know in the comments if you have any softwood cuttings on the go, and if you are seeing any results, or indeed if you have any questions.

I’ll be back in a couple of months with an update on rooting, I hope…

[UPDATE 22-05-17. hmm, well. I looked at these cuttings last evening. It was a sunny day and it was tremendously hot in the propagator, great gusts of hot and humid air poured out when I opened it up. Most of the cuttings in there seemed happy enough, but the cotinus look distinctly unwell. I don’t think they’re going to make it. This is either because the cuttings I took are too flimsy, I should have waited for stems to toughen up a bit, OR because it was too flippin’ hot in the bench. Possibly a combination of the two. I’ve turned down the thermostat by a couple of degrees. I’ll see how they get on, but I fear I will be taking another batch of cotinus cuttings soon…]

The Propagator

I’ve been raising plants from seed for a good few years with some reasonable results. I’ve also dabbled a bit with cuttings with very patchy results. I became a little obsessed with the topic of propagation in 2016 and resolved to improve my success rate and to share what I discovered.
This blog is my assorted ramblings, progress, disasters, setbacks, results and some tips along the way. The focus was initially propagation, which still features heavily but has expanded to cover the veg plot and the general state of the garden. The blog is mostly for my benefit, to keep track of what I've done, and hopefully is also of some interest to other planty obsessives. I post fairly frequently so click below to follow or sign up to receive updates by email. Comments welcome, I will respond to all.